There are basically three different data files used here:
1. The elevation profile, obtained from Earth Explorer
2. Northville-Placid Trail coordinates, obtained from The Hiking Project
3. Adirondack Park Boundary, obtained from Adirondack Park Agency
The Earth Explorer data were downloaded as separate files and merged together, with raster and rgdal packages in R. The NPT coordinates were read directly from the downloaded GPX file, and the ADK park boundary was read directly from the KML. An image of the NPT trail marker was downloaded from somewhere to spice up the map display.